1. Field of the Invention
The present invention relates to an exposure correction apparatus for a camera.
2. Related Background Art
A conventional interchangeable lens barrel is provided with a mechanical signal portion at an engaging portion with a camera body or with a memory means such as a ROM, so that data of the interchangeable lens barrel, e.g., a full-aperture value (F.sub.0) and a focal length (f.sub.mm) are input to the camera body.
The camera body receives these data from the interchangeable lens barrel, and calculates an exposure correction amount (Z) based on the full-aperture value (F.sub.0) and sometimes taking the focal length (f.sub.mm) into consideration.
Note that the exposure correction amount (Z) is an amount for correcting errors of an output from photometry means for measuring a light beam passing through a photographing lens of an interchangeable lens barrel and brightness of an image forming surface of the photographing lens (or film surface in a silver chloride type camera) with respect to brightness of a field as an object to be photographed or measured. Each interchangeable lens barrel has the exposure correction amount as an inherent value.
In order to obtain a bright finder, a recent camera tends to have a decreased diffusion property of a finder screen, i.e., narrow directivity, and the number of kinds of lens, including zoom lenses, is increased. In this situation, an increase in absolute value of an exposure correction amount, and a considerable reduction in correlation of the exposure correction value with the full-aperture value and the focal length are caused. That is, the exposure correction amount cannot be determined by a conventional exposure operation apparatus using a full-aperture value and a focal length.